In endoscopic observation of living organisms using an endoscope system, in order to precisely observe the state of the living organism, it is preferable to implement an observation method utilizing a plurality of kinds of light with different spectral characteristics.
Endoscopes that are capable of observation using a plurality of kinds of light with different spectral characteristics are disclosed in Patent Document 1 and Patent Document 2.
With the endoscope disclosed in Patent Document 1, in order to acquire a plurality of kinds of images by using the plurality of kinds of light with different spectral characteristics in the same endoscope, light from the acquired object is spectrally separated by a dichroic mirror. Because it is difficult to build the dichroic mirror into the tip of an insertion portion of the endoscope, it is disposed outside the body, and it is thus necessary to convey the light from the acquired object, which is received at the tip of the insertion portion, to the dichroic mirror outside the body via a fiber bundle.
The endoscope disclosed in Patent Document 2 is capable of observation using a plurality of kinds of light without employing spectral means such as a dichroic mirror, and therefore, a plurality of image-acquisition optical systems are disposed at the tip of the insertion portion of the endoscope.
Furthermore, from commercially available fluorescent agents, it is possible to produce fluorescent probes that emit light upon binding to material in a living organism; and by administering the living organism with a fluorescent probe that binds to a material related to a lesion and observing the fluorescence therefrom, it is possible to obtain information about the lesion.
Patent Document 1: Publication of Japanese Patent No. 3683271
Patent Document 2: Japanese Unexamined Patent Application, Publication No. 2001-190489